1. Field of the Invention
The invention provides for expressing recombinant proteins in eukaryotic cells. In particular, the invention includes methods and compositions for improved expression of proteins in eukaryotic cells by employing expression-enhancing nucleotide sequences. The invention includes enhanced expression and stability region (EESYR) sequences that facilitate enhanced and stable expression of recombinant proteins in eukaryotic cells, and methods of using such sequences.
2. Description of Related Art
The development of expression systems is an important goal for providing a reliable and efficient source of a given protein for research and therapeutic use. Recombinant protein expression in mammalian cells is often preferred for manufacturing therapeutic proteins due to, for example, the ability of mammalian expression systems to appropriately post-translationally modify recombinant proteins.
Several vectors are available for expression in mammalian hosts, each containing various combinations of cis- and, in some cases, trans-regulatory elements to achieve high levels of recombinant protein with short incubation times. Despite the availability of numerous such vectors, the expression of a recombinant protein achieved in mammalian systems is often unacceptably low or otherwise unsatisfactory. Moreover, developing a cell line that reliably expresses sufficiently high levels of a desired protein often requires time consuming cloning and amplification steps. Accordingly, there is a need in the art for improved mammalian expression systems.